Scanning and printing devices are widely used nowadays, especially in large enterprises and business organizations. They play important roles in making copies of documents for filing and in related printing and scanning operations.
On scanning and printing devices such as facsimile machines, printers, scanners, or multi function printers (MFP), to process paper that has to be read, copied or printed on both sides, one approach is to flip the paper manually; another approach is to install a mechanism in the device to flip the paper for double-sided printing or scanning. The techniques for such a mechanism are known in the art. Reference can be found in U.S. Pat. Nos. 6,032,949 and 6,463,256.
U.S. Pat. No. 6,463,256 aims to use the rigidity of the paper to push a paper guiding mechanism. It needs complicated operation elements and is prone to generate paper jams. U.S. Pat. No. 6,032,949 has an improved mechanism, but the production cost is higher. While these techniques can flip paper for double-sided printing, they have common problems. Namely, they adopt a complex design and mechanism, require many elements, maintenance is difficult, and the product is bulky. Because of too many operation elements are involved, paper jams frequently occur. For processing scanning and printing on the second side of the paper, wrinkles are generated. These problems remain to be overcome.